libreboot-utils: unified error handling

i now use a singleton hook function per program:
nvmutil, mkhtemp and lottery

call this at the startup of your program:

(void) errhook(exit_cleanup);

then provide that function. make it static,
so that each program has its own version.

if you're writing a program that handles lots
of files for example, and you want to do certain
cleanup on exit (including error exit), this can
be quite useful.

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/libreboot-utils/lib/word.c

@@ -63,6 +63,6 @@ check_nvm_bound(size_t c, size_t p)
 	check_bin(p, "part number");
 
 	if (c >= NVM_WORDS)
-		b0rk(ECANCELED, "check_nvm_bound: out of bounds %lu",
+		err_exit(ECANCELED, "check_nvm_bound: out of bounds %lu",
 		    (size_t)c);
 }